Thread-cutting mechanism for sewing-machines.



. L. BARIION.

1IHIII'AD CUTTING MECHANISIVI FOR SEWING MACHINES.

APPLICATIDN FILED FEB. 1,1913.

Patented June 5, 1917.

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W. L. BARRON. l THREAD cumNc MECHANISM Foa SEWING MACHINES. APPLICATION FILED FEB. 1913. I LQ28,871 1 Patented June 5, 1917.

me Non/us sums ca, www,LA ma msmmzm/v. u c4 VTILLIAIVI L. BARRON, 0F NEW YORK, N. Y., ASSGNOR TO TEE SINGER MANUFAC- TUBING COMPANY, A CORPORATION OF NEWf JERSEY;

THREAD-CUTTING- MECHANISM FOR SEWING-MACHINES.

Specification of Letters Patent.

Patented June 5, 1917.

Application filed February 7, 1913i Serial No. 746,696.

To all whom it may concern.'

Be it known that l, WILLIAM L. Bannon, a citizen oi' the United States, residing at New York, in the county ot .New York and State oit New York, have invented certain new and useful improvements in Thread- Cutting Mechanisms 'tor Sewing-Machines, of which the following is a specicatiomreterence being had therein to the accompanying drawings.

My invention relates to sewing machines and more particularly to an automatic needle-thread nipping and cutting attachment for use in that class of machines which sew detached groups of stitches, such for example as sewing on buttons, tacking, barring, ozc., the object of the invention being to provide an attachment to nip and sever the loose end of the needle thread at the beginning ot the sewing of the group ot stitches, and to sever the needle-thread at the completion of the group ot' stitches.

rEhe invention will be understood by reference to the accompanying drawings in which Figure 1 is a rear side elevation, and Fig. 2 a bottom plan of a iat button sewing machine of the Singer type; Figs. 3 and 4: bottom plan views of the thread-nipping and severing attachment with the parts in different positions; Fig. 5' a perspective view oit the attachment with the parts in position immediately after the cutting of the needlethread', Figs. 6 and 7 sections on the planes of thc lines (3 6 and 7-7 of Fig. 3, respectively; Fig. 8 a perspective view of the thread-nipper and part of the throat-plate; F ig. 9 a similar view of the needle-hole portion of the throat-plate; and Fig. 10 a. tace view of a portion of the cam forgiving movements to the parts o the attachment. Similar reference numerals indicate similar parts in the several views.

For convenience of illustrating one application of the use of the present invention, l have selected a well known form of Singer lock-stitch sewing machine iitted with an attachment for sewing on buttons. As shown,A

the machine comprises a needle 1 carried by a vertically reciprocating needle-bar operated from the driving shaft 2 which shaft is journaled in the upper part of the arm 8, and an oscillating shuttle itted within the sl'mttle-race l depending from the bed-plate 5, the said shuttle deriving its operative movements troni the driver G connected,

tion lever 12 is adapted to 'assume its rearward or operative position under the action oi' a spring, and is detained in its forward or inoperative position by a detent-lever 15 ulcrumed at 16 and maintained normally in operative engagement with the upper portion vof the stop-lever by means ot' the spring Y17 in a manner well-known. The stop-lever 12 is so mounted within the projection 11 as to be capable of slight sidewise movement which is yieldingly resisted in the stitching operation by the springpressed plunger-pin 18, shownin end view only in Fig. 1.

As shown 'in Figs. 3, 4i and 5 the superposed tapered blades 19 and 2O are fixed upon an arm 21 attached to a sector-gear 22, which gear is journaled upon a pin 23 within a bracket 24 attached to the under side oit the throat-plate 25. Meshing with said sector-gear is a rack 2G (see Fig. 2) formed upon a lateral arm carried by the sliding bar Q7 supported beneath the work-plate of the machine and havingl near its rearward end a block 2S with a lateral notch. This notch is entered by the contracted lower end of a lever 29 pivotally mounted upon the fixed fulcruni-stud 30, carried by a bracket 3l attached to the bed-plate 5, 'and provided at its upper end with a pin or roller-stud entering the cam-groove 33 in the rear face of the rotary cam-wheel 34, the latter being mounted upon a fixed stud carried by the frame of the machine. rEhe cam-wheel has attached to its front side, as indicated in dotted lines in Fig. 1, a worm-wheel 35 meshing with a worm 36 fixed upon the main-shaft 2. The block 28 has a rearward extension carrying a pin or roller-stud 37 (see Fig. 2) embraced by the forked arm 38 of a bellcrank-lever fulcrumed at 39, and having a second arm 40 provided with a spring-pressed pin ll-l entering a slot 4t2 in the lower end of stopslever 12.

The lever 29 and bellcrank-lever 38-40 Aconnections also serve to impart the movements to the needle-thread nipping and cutting attachment 'at the beginning of each series of stitch-forming operations as will now be described.

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As shown in Figs. 3, 4 and 5 the under side of the throat-plate is preferably cut out at 43 to accommodate a spring-pressed jaw 44, pivoted at 45, and normally held out of engagement at its forward end, by

the spring 46, with a fixed jaw 47, whichV latter may be for convenience a separate piece fastened to the throat-plate. `Ri'gjdly secured to the arm 21 which carries the lower thread-cutting blade 19 and the needle-thread cutting blade 20, is a threadcarrying arm 48 disposed adjacent the under side of the throat-plate and adaptedV in its movements to pass over the thread-'nipping jaws 44 andv 47. At its forward end the arm 48 is formed with a hook or barb 49 which barb, on the initial movement of arm 48, engages the loose end of the needle-thread and draws it between the nipping jaws. On its outer edge the arm 48 is formed with a cam surface 50 which surface, when the parts are in normal position shown in Fig. 3, lies beyond a stud 51 extending laterally from the side ofthe movable jaw 44 so that said aw at such time will be open. `When thearm 48 is retracted, or moved to the right as viewed in the drawings, the cam surface 50 will engage stud 51 immediately after the barb 49 has drawn the needle-thread between the gripping jaws, and the contact of the cam surface 50 with said stud will holdvthe aw 44 closed upon the needle-thiead. The barb 49 forms one member of a shearing or cutting mechanism, the other member consisting of a blade 52 in the' form of a flat plate having a notch 53 located a short distanceV toone side of the gripping faces of the jaws 44 and 47. The cutting blade lies directly under Vthe plane of movement of arm 48, that is these two parts are substantially in engagement with A'each other whenever.

the arm 48 is movedl over the blade Figs. (3 and 7). n the arm 48 has rdrawn the thread between the nippingjaws and the latter have closedvr upon the needle thread, the further travel teenV stitches each.

V,the thread between saidjaWs. Y

.ment of arm 48 continues-while Vfollower 3:2

.cated in Fig. 7. Y tially the Vposition shown in Fig. 4 while the Vfollower 321s on the dwell 57 of cam 34,

As explained hereinafter, afterl sition, as shown iii Fig. 4, to hold the jaws` closed for a predetermined number of stitches. Y

The cam 34 may be geared so that the machine will sew one, two, three or more groups of stitches for one revolution of the cam. In the machine illustrated, the cam is geared 1 to 42, and the cani-groove 33 is so divided asto sew three groups of four- ()ne ofthe sections over which'the stud or cam-follower travels to effect the desired movements ofv b -ades 19 and 20 and arm 48 is shown on an enlarged scale in Fig. 10. nUpon the'completion cfa.

group of stitchesthe parts above described as under the throat-plate are in the positions shown in Fig. 3, that is, with lthe barb 49 at the left of the needle-hole 54. At such time the cani-follower is on the dwell 55. When the machine is started the needle descends, the loose end of the needle thread being vabove the work-plate. fis the needle vbegins to rise the thread-loop thus formed is seized by the point of the shuttle and extended sufficiently for the latters passage, slack being provided for such operation by vthe partial descent of the vtake-up arm in this stage of the stitch-forming cycle. The

passage of the shuttle'through the loop of needle thread draws the loose end ofthe thread down through the needle-hole As the take-up rises, cam-follower travels over the inclined cam section 55 thereby Vmoving lever 29 and the parts before described as actuated thereby, to move rack 26 to impart an initial rotary movement to sector-gear 22. Cam-follower 32 then passes on to the dwell 57 of the cam-groove. r1`he movement of sector-gear 22 will swing arm 48 so that-its barb 49V will cross the needlehole 54 in a path beneath the movable and fixed jaws 44 and 47 thereby Vengaging the lfoose'end of the needle thread and drawing the latter'to'one side, as shown in Fig. 7, and between the nipping aws 44 and 47. lVhen the thread is so placed, cam surface 50 will engagepin 51, closing the jaw 44 upon jaw 47 to vthereby iirmly grip andV hold The moveis on the cam section and this further travel will effect the cutting Vofthe thread betweenV thebarb 49V and blade 52, as indi- Arm 48 remains in substanand in this .position the cam surface 540 of said arm, byV bearing against pin 51, will hold the vend of the needle-thread gripped Y ln practice stitches as may be desired before follower 32 leaves the dwell. In the machine illustrated two stitches will be made while the cam-follower is on dwell 57.

Vhen cam-follower 32 reaches the inclined section 58 of the cam-groove, sectorgear 22 will be given a second movement through the described connections, to thereby impart a further movement to arm 48 in the same direction as it was moved when the said follower was passing over the inclined section 56. rlhis second movement carries the parts to the position shown in Fig. 5, that is, to the extreme right, where they remain as long as follower 32 is on the dwell 59. In this movementv the cam surface 50 passes out of contact with pin 51 and as a result jaw 44 is opened by a spring 46. 1t is to be understood that blades 19 and 20 being rigidly secured to arm 21 will also take the position shown in Fig. 5, to be moved` forward at the close of the stitching cycle. to sever the lower and the needle threads.

r-issuming for the purpose of describing the operation of the machine that cam 34 makes but one revolution for each group of stitches, the cutting blades and arm 44 will remain in the position shown in Fig. 5, while the machine sews the stitches in the partic ular work forl which it is adapted, that is button sewing, tacking, barring, &c., that is, while the follower 32 is on dwell 59. When the follower reaches the cam or inclined section 60, blades 19 and 20 will be advanced sufficiently to enable the former to engage the lower or shuttle thread. These blades will then have a short period of rest while the follower is on the short dwell 61, and then moved so that, on the next descent of the needle, blade 20 will engage the needle' thread loop, and the two threads will be severed by the overthrow of the stop-lever when follower 32 reaches dwell 55 opposite the enlarged depression G2. That is, the blades 19 and 20 will be given a quick movement to their extreme forward position to sever the threads and then restored to normal position shown in Fig. 3, as fully described in Patent No. 807,676, before referred to, and in patent to C. M. Horton, No. 1,001,034, dated August 22, 1911. In these movements of blades 19 and 20, at the close o-f the stitching cycle, arm 48 will also be moved, crossing the needle-hole 54 after the needle-thread has been severed, and then assuming its normal position showninlig. 8. In such position the nipping jaws are open.

While I have described the cutting blades 19 and 20 they form no part of the present invention, the latter being confined to the described mechanism for successively nipping and cutting the needle-thread, and then holding the end of the needle-thread for a predetermined period at the beginningA of the stitching cycle. It is to be understood that one of the chief objects of the improvement as thus described is to effect a uniformity of the finished work unattainable by mechanism heretofore in use. yBy means of the present mechanism, the loose ends' of the needle-thread left below the fabric are invariably cut off close to and at the same distance from the lower face of the fabric, thereby 'obviating the necessity heretofore existing of clipping such lose thread ends by hand.

As will be observed, the action of the cani surface 50 upon the stud 51 causes a practically positive gripping action of the nipping jaws upon the thread, so that any pull upon the latter in the shearing action of the blade 52 and arm 48 is effectively resisted by the nipper and a clean cut is thereby insured, producing a uniform thread-end attached to the fabric.

Having thus set forth the nature of the invention, what I claim herein is 1. In a sewing machine in combination, a reciprocating needle and complemental stitch-forming mechanism, and mechanism for successively nipping the needle thread and severing the loose end at the beginning of a stitching cycle, said mechanism including a thread-drawing member and a nipping element moving relatively to and actuated by said thread-drawing member.

2. In a sewing machine in combination, a reciprocating needle and complemental stitclrforming mechanism, and mechanism for successively nipping the needle thread and severing the loose end at the beginning of a stitching cycle, and for holding said thread for a predetermined time after the loose end has been severed, the nipping device of said mechanism being mounted independently of the severing means.

3. In a sewing machine, in combination, a reci arocating needle and complemental stitchorming mechanism, thread-severing mechanism, thread-nipping mechanism comprising a nipping wall and a nipping jaw independent of the severing mechanism and moving in a plane intersecting the said nipn ping wall, the said severing and nipping mechanism acting upon the thread to successively nip the same below the worl-plate at the beginning of a stitching cycle, then to cut the loose end of said thread and to hold the end of the thread for a predetermined period. j

4. In a sewing machine, in combination, a reciprocating needle and complementa-1 stitch-forming mechanism, a thread-nipping device comprising a movable jaw and a jaw coacting therewith, a thread-drawing member movable in a path entirely outside of the range of action of said jaws for drawing the needle-thread between said jaws, and means for closing said jaws upon the thread and holding them closed fora predetermined period.r

5. In a sewing machine in combination, a reciprocating needle and complemental stitch forming mechanism, a`V thread nipping device comprisinga movable jaw and a jaw coacting therewith, means movable relatively to said jaws for drawing the needlethread between the same, means for closing said jaws upon the thread and holding them closed for a predetermined t period, and means for cutting the loose end of the thread while it is so held.

6. In a sewing machine inl combination, a reciprocating needle and complemental .stitch-forming mechanism, a needle thread nipping device comprising ay movable jaw anda jaw coacting therewith, an arm and means for moving the same to cause it to engage and draw the thread between said jaws, a cam surface on said arm adapted to engage one of said jaws to close it uponthe other after the thread has been drawn between them, and means for holding the jaws closed for a predetermined time. j

7. In a sewing machine in combination, a reciprocating needle and complemental stitch-forming mechanism, a thread-nip ping device comprising a movable jaw and a jaw coacting therewith, a member mov-V able relatively to said jaws and means to actuate the same to engage and draw the needle-thread between said jaws Aduring a portion of its travel, and to effect the cutting of the loose end of the thread upon its further Y travel.

a 8. In a sewing machine in combination, a reciprocating needle and complemental stitch-forming mechanism, a needle thread nipping device comprising a movable jaw y and a jaw coacting therewith, an arm and means for moving the same to cause it to engage and draw the thread between ,said jaws, a cam surface on said arm, adapted to engage one of said jaws to close it upon the other after the thread has been drawn between them, means for severing the loose end of the thread while it is so held, and means for yholding the jaws closed upon the thread for a predetermined time 'after the loose end has been severed.l

9. In a sewing machine in'combination, l a reciprocating needle and complemental stitch-forming mechanism, a thread-nip-V ping device comprising normally open jaws, a needle-thread engaging arm and 'means for moving the same to'engage said thread and draw it between said jaws, 'meansY for closing said jaws-'upon the thread, and a thread-cutting blade to Veffect they cutting of the loose lend of the thread Vupon the furtherv travel of said arm.

l0. In a sewing lmachine 4in combination, a reciprocating needle and! complemental Ystitchsforming mechanism, Ya thread-nip- Y ping device comprising a rmovable jaw and a jaw coacting therewith, a thread-engaging arm and means for moving the saine to engage the needle thread and draw it between said jaws, saidv arm having a cam surface to close said jaws after the thread is drawn between them, and a cutting blade in proximity to said jaws to effect the cutting of the'loose end of the thread upon the further travel of said arm. Y

11. In a sewing machine, in combination,

a reciprocating needle Vand Vcomplemental stitch-forming mechanism, a thread-nipping and cutting device located beneath fthe work-plate and adjacent to the point of descent of the needle, a stop-motion device whereby groups of a predetermined number of stitches may be formed, said nipping device comprising normally open jaws, one jaw being movable relatively to the other, a needle-thread engaging arm and means for moving the same to engage and draw the thread between the jaws, means for closing the jaws and for holding them closed to nip said jaws, said arm having Va Cam-surface adapted to close the movable jaw upon the fixed jaw, and a cutting bladein proximity to said jaws to etl'ectfthe cutting of the loose end of the thread upon the furthertravel of said engaging arm. Y 1V 13. In a sewing machine, in combination, stitcheforming mechanism, including a reciprocating needle,'a lined cutting blade, a thread-drawing and cutting element coperating with said fixed blade, a blade movable to cut the thread independently of said fixed blade, and means for imparting to'said movable blade and thread-drawing Velement successive operative movements to out theV `needle-thread at different points. Y

1 le. In a sewing, machine, in oombina` tionV stitch-i`orming mechanism including a reciprocating needle, two threadecutting members movable in unison and adapted for action'uponthe thread, and means for imparting .to said `thread-cutting members a cutting Vmovement at jthe Vcompletion of iio one group of stitches'and another cutting movement atsubstantially, the beginning oit'Y the production of another Vgroup of stitches Y Y of predeterminedV number toy causeV Ysaid members to sever Y the Aneedle-thread successively in diEerentfstitch-orming cycles.

1;5'. In 'a sewing machine, incombination,

stitch-forming mechanism including a reciprocating needle, a movable cutting blade, a fixed cutting blade and a thread-drawing member adapted to coact therewith, and an actuating cam and a connection including a common element between said cam and the movable blade and thread-drawing member whereby successive operative movements are imparted to said blade and member for cutting the thread at dierent points.

16. In a sewing machine in combination, stitch-forming mechanism including a reciprocating needle, two thread-cutting devices and a nipping device, comprising a j aw movable in a plane intersecting a eoaeting nipping surface, all adapted for action upon the needle thread, and means for actuating sa id threadecutting devices successively in cutting the needle thread at dierent points and for actuating the nipping device to nip the needle thread intermediate the cuttin actions. i

17. In a sewing machine, in combination, stitch-forming mechanism including a reciprocating needle, two thread-cutting mem bers movable in unison and adapted for action upon the thread, and means for impart- Copes of this patent may be obtained for ing to said thread-cutting members a cutting movement in one direction at the completion of a group of stitches and another cutting movement in the opposite direction at substantially the beginning of the production of another group of stitches of predetermined number, to cause said members to act upon the needle-thread successively in different stitch-forming cycles.

18. In a sewing machine for forming a predetermined number of stitches, the com bination with stitch-forming mechanism, of movably mounted thread-severing means, and automatically operated mechanism for moving said thread-severing means to trim off the beginning end of the needle-thread during the rst part of a stitching operation and to sever the needle-thread at the end of a stitching opera-tion.

In testimony whereof, I have signed my name to this specification, in the presence of two subscribing witnesses.

WILLIAM L. BARRON.

IVitnesses HENRY A. KORNEMANN, Jr., IVHJLTAM I. STEWART.

ve cents each, bfaddressing the Commissioner of Patents,

Washington, D. C. 

